Renewable fuse



G. R. BROWN RENEWABLE FUSE Aug. 1, 1939.

Filed March 23, 1938 inventor George F?. Brown, y a MLM Vhs Atbofney.

Patented Aug..1, 179-39 UNITED STATE-s PATENT OFFICE General Electric Com New .York

pany,aeorporatinnd Application ma z3, 193s, serial No. 1s'1`,s5z 7 claim.. (ci. zoo-1an 'I'his invention relates to a fuse for protecting electrical circuits, and more particularly to a cartridge type of fuse employing a renewable fuse link.

It is an object of my invention to provide an improved construction and arrangement inA devices of this type in which the link may be easily and quickly replaced upon blowing of the fuse.

In the accompanying drawing Fig. 1 is a crosssectional view through the fuse; Fig. 2 is a sectional view on the line 2 2 of'Fig. 1, Vand Fig.' 3 is an exploded view showing one end of the fuse with the cap removed illustrating the manner oi renewing the fuse link. Referring to the drawing the fuse casing comprises a housing Ill of insulating material, which may be formed of libre or the like,'and which'may take the form of a tubular member, although housings of other shapes may be employed- A metallic ferrule II forming Prt of the casing is provided ateach end of the housing for the purpose of reinforcing the casing and for providing a contacting means for cooperation with a fuse holder. 'Ihe f'errules are shaped to the contour of the body of the housing and in the form illustrated are tubular. Inasmuch as both end structures of the fuse are identical, one end only will be described, it being understood that the other end of the fuse is similarly constructed.

The ferrule-II is provided with a slot I2 which extends half way around the periphery ot the Ierrule to provide a loose mounting for a supporting plate I3. In order to conform to the contour ofthe bferrule, the plate I3 is provided with a semicircular edge Il'which coincid with the periphery of the ferrule when the plate is in fuse-holding position. The other edge *I5 of the plate extends substantially across the end of the opening formedby the casing III and is provided with indentedabutments Il which coact with'the walls Il of the slot I2 to prevent the plate from falling out of the Slot interiorly of the Ierrule Il. YIn order to prevent theplate from beingv withdrawn from the slot exterlorly of the Ierrule, a pin Il 'is provided through the plate which engages the wall ofthecasing asthe plate is drawnoutwardly, as best shown .in Fig. 3. Inasmunh's the plate may be moved transversely to the axis of the casing to uncover the end thereof a relatively lo large opening is provided by the un end of the casing through which the fuse link Il may be inserted in the :use structure.'

.In order to maintain the supporting plate 4I3 in -normal Vfuse holding position and in order to clamp the'fuse tothe plate. a cap 2l .is provided the pin I8 which prevents its removal'from the having internal screw threads 2| cooperating with external threads 22 formed on the ferrule II. The cap Yis provided with vent openings 23 which are separated from the interior of the fuse housing by a screen 24. A bearing plate 25 is provided in the base of the cap to cooperate with the supporting plate I3` in clamping the fuse link. The screen serves to separate the bearing plate .25 from the vented end wall of the cap in order that gases'may be vented through the openings 23. The bearing plate 25 and screen 24 are secured to 'the end of the cap by a rivet 2B which is provided at its interior end with an indentation 21 adapted to cooperate with the pin I8 in4 holding a fuse link in position.

The fuse link I Il is provided with an end por- `tion 28 which may be bent atan angle to the main body of the fuse and which is provided with a boss 2S which ts over the pin I8 and rests within the indentation 21 so that as the cap is screwed upon the ierrule the end of the link is locked securely between the bearing plate 25 and the supporting plate I 3. It is desirable thatran excellent electrical contact be maintained between the end of the fuse and the cap structure. To this end the bearing plate 25 is provided with a plurality of annular grooves :ill which score the sui'iace'of the end of the fuse link as the cap is rotated and threaded down upon the ferrule thereby making clean line contact with the end -oftheiuselink By the construction ot this invention it is possible to easily and quickly replace the fuse link I! whenever it is blown. By unscrewing the cap at each end of the casing 2l it is possible to slide the supporting plates I3 transversely to the axis of the fuse casing to a position where they uncover the ends of the casing, such a position being shown by Fig. 3. In this position ample' room is provided for removing the fragments of the blown fuse and for replacing the fuse link through the opening made by the transverse removal of the supporting plate I3. The supporting plate I3 is locked the slot in the ferrule by means of outside or exterior of the terrule and by the shoulders I6 and the edge I5 which prevent Aremoval o1' the supporting plate from the inside or interior oi the ferrule. Accordingly. there is no danger of the Supporting plate becoming disassembled or lost. The semi-circular wall Il of the supporting plate cooperates with the wall of the cap 2l in maintaining the bearing plate in fuseholding position, as 'shown by Fig. 1.` Ample opportunity for venting the gas ery at one end thereof, a supporting element disiempwingprine funespwvided syinevents n' while means lz and ine supporting piste l:

'have been shown as'semi-circular in shape for the purposes of illustration, it will be apparent that theseelements may take other forms in whichthe supporting plate is movable trans'- versely oi the i'use casing without departing from the spirit oi the invention.'v A fuse constructed according to this invention is one in which the fuse link may beeasily and quickly rep out the 'use of specialtools or equipment, it being merely necessary to unscrew'the closure cap at each end of the i'use and -move the supporting plate to expose the interior of the casing.

WhatIclaim asnewanddesiretosecure by IettersPatent ofthe United States is:

1.` In a fuse structure, a tubular casing, 'a

threaded ferrule at one end oi said casing, said ferrule being provided with a semicircular slot, a supporting element slidable in said slot transversely ot said casing and partially ciosing the end-oisaid casing. l cap threaded on said fernileindafuselinkdisposedinsaidcasing and 'having a bent-over end clamped between said supporting element and said cap as said cap isA threaded on said f eriule. Y

2. In a renewable fuse, adcasing, saidcasing n'eving s peripheral slet et one'end, n supporzing element mounted in said s lot Vior" movement transv erselyofsaidciising,s.capclosingtheendetv said casing and maintaining said element in'op-A erativ'epositmandaiuselinkhavinganend clamped between said cap and'said element, said cap being removable from said casing whereby said supporting element may be slid transversely 'throughsaid-slot ior'removal of said llink 3. A renewable fuse comprising acasing 'a slot extending around a poi-'tion of the periphposedinsaidslotandsubstantiaily'clcsingthe end of said casing, said supportin `element being movable transversely of the casing through said slottouncovertheendofsaidcasing,meansonsaid element maintaining said-supporting element withinsaidsloaacapsurroundingtheendofthe easingandiifuselinkwitliinsaidcasing and having an end clamped between said sup. portingelement and said capi` 4. In a renewable fuse structurefa tubular'casing of insulating material, a ferrule disposed on one end of said said ferru'le having a slot 'through the periphery thereof. a supporting'element normally disposed within said slot and substantially closing the end'of said casing; -said sup-- porting element vbeing movable transversely of the casing through said slot to uncover the'end of i th-v .Platea and a fuse link gripping the endsof said-casing, a cap secured said ierru'le, and a fuselinkdisposedinsaidcasingandhavingan end clamped between said `cap and said supporting element, said cap extending around the pe-` riphery of said fer-rule and maintaining said sup- .porting element in normal position.

5. In s' device of class described, aI tubular icas-A ing of insulating" material, a ferrule on one end ofi said casing provided with a peripheral slot, a supporting element normally disposed within said-slot for substantially closing the end of said casing, said element being movable transversely of said casing-through said slot to expose the end of said casing for insertion of a fuse link therein, a iuselink disposed in said casing having an end overlying said supporting element when in normal position, and a ca'p provided with .grooved means mounted on said ferrule to clamp the end of said link between said grooved means and said supporting element, said cap maintaining said 2 supporting element in normal position.

6. In combination, a casing having a'peripheral slot at one end. a supporting element located in said slot and partially closing the end of said casing; said element being slidable transversely oi? the casing through said slot to expose the "exid of said casing, means Von sai d element coasting with the wall ot saidrcasing to prevent removal of said element frornsaid slot, a cap secured to the end of said -casing .and adapted to' maintain said element in closing position, said cap being provided with a vent opening, a screen closing said opening, a bearing plate secured to said capl and overlyingy said screen and opening, and a.K fuse link dispcd in said easing having anend bearing plata.

V'1. In combination, a tubular casing of insulat-` clamped between saidsupporting element and said ing'material, threaded ferrules secured to eachA end of said casing, eachlof said ferrules being provided with a peripheral slot, a supporting element at each end ot the casing partially closing the endsof said casing and slidable in said slots A transversely of said casing, projecting vmeans mounted in each ofsaid supporting elements, a,

screen to a corr cap, said fastening 5g means beingindented for cooperation with said projecting means, grooves formed in said disposed in said housing and having. bent-over ends clamped between said projecting means -and indented. fastening means said'liiik;V

f GEORGE supporting elements and said bearing'plates as t5 said caps are threaded on said ferrules. with said 

